/*
 *
 * @APPLE_LICENSE_HEADER_START@
 *
 * Copyright (c) 1999-2001 Apple Computer, Inc.  All Rights Reserved. The
 * contents of this file constitute Original Code as defined in and are
 * subject to the Apple Public Source License Version 1.2 (the 'License').
 * You may not use this file except in compliance with the License.  Please
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 * read it before using this file.
 *
 * This Original Code and all software distributed under the License are
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 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS
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/*
	File:		TimeoutTask.h

	Contains:	Just like a normal task, but can be scheduled for timeouts. Unlike
				IdleTask, which is VERY aggressive about being on time, but high
				overhead for maintaining the timing information, this is a low overhead,
				low priority timing mechanism. Timeouts may not happen exactly when
				they are supposed to, but who cares?
					
	
	
	
*/

#ifndef __TIMEOUTTASK_H__
#define __TIMEOUTTASK_H__


#include "StrPtrLen.h"
#include "IdleTask.h"

#include "OSThread.h"
#include "OSQueue.h"
#include "OSMutex.h"
#include "OS.h"

#define TIMEOUT_DEBUGGING 0 //messages to help debugging timeouts

class TimeoutTaskThread : public IdleTask
{
	public:
	
		//All timeout tasks get timed out from this thread
					TimeoutTaskThread() : IdleTask(), fMutex() {}
		virtual		~TimeoutTaskThread(){}

	private:
		
		//this thread runs every minute and checks for timeouts
		enum
		{
			kIntervalSeconds = 60	//UInt32
		};

		virtual SInt64 			Run();
		OSMutex					fMutex;
		OSQueue					fQueue;
		
		friend class TimeoutTask;
};

class TimeoutTask
{
	//TimeoutTask is not a derived object off of Task, to add flexibility as
	//to how this object can be utilitized
	
	public:
	
		//Call Initialize before using this class
		static 	void Initialize();
		//Pass in the task you'd like to send timeouts to. 
		//Also pass in the timeout you'd like to use. By default, the timeout is 0 (NEVER).
		TimeoutTask(Task* inTask, SInt64 inTimeoutInMilSecs = 60);
		~TimeoutTask();
		
		//MODIFIERS

		// Changes the timeout time, also refreshes the timeout
		void		SetTimeout(SInt64 inTimeoutInMilSecs);
		
		// Specified task will get a Task::kTimeoutEvent if this
		// function isn't called within the timeout period
		void		RefreshTimeout() { fTimeoutAtThisTime = OS::Milliseconds() + fTimeoutInMilSecs; Assert(fTimeoutAtThisTime > 0); }

	private:
	
		Task*		fTask;
		SInt64		fTimeoutAtThisTime;
		SInt64		fTimeoutInMilSecs;
		//for putting on our global queue of timeout tasks
		OSQueueElem	fQueueElem;
		
		static TimeoutTaskThread*	sThread;
		
		friend class TimeoutTaskThread;
};
#endif //__TIMEOUTTASK_H__

